1. Field of the Invention
The present invention relates to a box car for carrying bulk material and capable of being incorporated into a freight train of a plurality of successively arranged like box cars. The box car comprises a chassis, an elongated box for storing the bulk material, the elongated box extending in a longitudinal direction and being mounted on the chassis, and the box having an open top and a bottom region, and a conveyor arrangement extending in the longitudinal direction in the bottom region, the conveyor arrangement comprising a substantially horizontally extending endless conveyor having two ends spaced from each other in the longitudinal direction and a drive for moving the endless conveyor in a conveying direction, one of the endless conveyor ends being a rear end in the conveying direction and another one of the endless conveyor ends being a front end in the conveying direction. A bulk material transfer device is provided for transferring the bulk material from a preceding box car to a succeeding box car, the preceding and succeeding box cars being coupled to each other, the bulk material transfer device comprising an inclined endless conveyor having a lower end and an upper end, and a drive for moving the inclined endless conveyor.
2. Description of the Prior Art
A box car of this type has been disclosed in U.S. Pat. No. 4,576,538. According to the patent, the bulk material transfer device is a conveyor band projecting over the open storage box of the succeeding box car to fill this storage box. The conveyor arrangement in the bottom region of the box car is also a conveyor band, which may be driven at a different speed so that the storage box may be filled when the conveyor band proceeds at a lower speed to push the transferred bulk material heap slowly ahead in the longitudinal direction. On the other hand, when the conveying speed is increased, the bulk material may be moved to the preceding box car without storage. A freight train comprised of a suitable number of such box cars may be advantageously used, for example, to convey ballast and/or detritus excavated by a ballast cleaning machine from a box car at the excavating site at one end of the train to preceding box cars where the ballast and/or detritus is stored.
In the box car of British patent No. 2,277,725, the transfer device subtends one end of the bottom conveyor arrangement and is pivotal about a horizontal axis extending transversely to the longitudinal direction so that the transfer device may be driven from a first, elevated position for transferring the bulk material to an adjoining box car to a second, lowered position for discharging the bulk material directly on a track bed while reducing the height of the fall of the discharged bulk material.
U.S. Pat. No. 5,151,002 discloses still a further embodiment of such a box car, in which two parallel bottom and transfer conveyors are driven in opposite directions. One end of one of the bottom conveyors is subtended by the associated transfer conveyor while the transfer conveyor associated with the other bottom conveyor overlaps an opposite end thereof. A longitudinally extending wall separates the storage box into two halves so that each bottom conveyor has its own storage box. This makes it possible to convey and store bulk material independently in two opposite directions.